package com.xpgk.mvc.bsendMessage;

import java.io.IOException;
import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;


import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;
/**
 * DES加密介绍 DES是一种对称加密算法，所谓对称加密算法即：加密和解密使用相同密钥的算法。
 * 注意：DES加密和解密过程中，密钥长度都必须是8的倍数
 * @author Administrator
 *
 */
public class DESUtil {
private final static String DES = "DES";
    
    
     
    /**
     * Description 根据键值进行加密
     * @param data 
     * @param key  加密键byte数组
     * @return
     * @throws Exception
     */
    public static String encrypt(String data, String key) throws Exception {
        byte[] bt = encrypt(data.getBytes(), key.getBytes());
        String strs = new BASE64Encoder().encode(bt);
        return strs;
    }
 
    /**
     * Description 根据键值进行解密
     * @param data
     * @param key  加密键byte数组
     * @return
     * @throws IOException
     * @throws Exception
     */
    public static String decrypt(String data, String key) throws IOException, Exception {
        if (data == null){
            return null;
        }
        BASE64Decoder decoder = new BASE64Decoder();
        byte[] buf = decoder.decodeBuffer(data);
        byte[] bt = decrypt(buf,key.getBytes());
        return new String(bt);
    }
 
    /**
     * Description 根据键值进行加密
     * @param data
     * @param key  加密键byte数组
     * @return
     * @throws Exception
     */
    private static byte[] encrypt(byte[] data, byte[] key) throws Exception {
        
        SecureRandom sr = new SecureRandom();// 生成一个可信任的随机数源
        DESKeySpec dks = new DESKeySpec(key);// 从原始密钥数据创建DESKeySpec对象
 
        // 创建一个密钥工厂，然后用它把DESKeySpec转换成SecretKey对象
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
        SecretKey securekey = keyFactory.generateSecret(dks);
 
       
        Cipher cipher = Cipher.getInstance(DES); // Cipher对象实际完成加密操作
        cipher.init(Cipher.ENCRYPT_MODE, securekey, sr);// 用密钥初始化Cipher对象
 
        return cipher.doFinal(data);
    }
     
     
    /**
     * Description 根据键值进行解密
     * @param data
     * @param key  加密键byte数组
     * @return
     * @throws Exception
     */
    private static byte[] decrypt(byte[] data, byte[] key) throws Exception {
       
        SecureRandom sr = new SecureRandom(); // 生成一个可信任的随机数源
        DESKeySpec dks = new DESKeySpec(key);// 从原始密钥数据创建DESKeySpec对象
 
        // 创建一个密钥工厂，然后用它把DESKeySpec转换成SecretKey对象
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
        SecretKey securekey = keyFactory.generateSecret(dks);
 
       
        Cipher cipher = Cipher.getInstance(DES); // Cipher对象实际完成解密操作
        cipher.init(Cipher.DECRYPT_MODE, securekey, sr);// 用密钥初始化Cipher对象
 
        return cipher.doFinal(data);
    }
    
    
    public static void main(String[] args) throws Exception {
        String data = "123 456";
        String key = "wang!@#$%";//key的长度大于等于8
        System.err.println(encrypt(data, key));
        System.err.println(decrypt(encrypt(data, key), key));
        
        
    }

}
